Disclaimer: This is my first attempt at doing anything with php, which might be overkill for what's required. Many of the pages of our website have one or more products with multiple selections (drop-down lists). Quite a few orders come in without a selection for one of the critical choices, which necessitates contacting the customer and waiting for a reply. A script which validates required fields could make things run much more smoothly for everyone.
I've downloaded such a script and attempted to validate just one list (outside color) but have been unable to get the validation to work. Any guidance will be much appreciated. The files in question are attached for convenience.